A 3rd Generation Partnership Project Long Term Evolution (3GPP LTE) system (conforming to Rel-8 or Rel-9) adopts Multi-Carrier Modulation (MCM) in which a single CC is divided into a plurality of frequency bands. On the other hand, a 3GPP LTE-Advanced system (hereinafter, referred to as an LTE-A system) may use CA by aggregating one or more CCs to support a broader system bandwidth than in the 3GPP LTE system. The term CA may be interchanged with carrier matching, multi-CC environment, or multi-carrier environment.
For a single-CC environment such as the LTE system, only multiplexing of UCI and data using a plurality of layers on one CC is specified.
When UCI is multiplexed with data, the number of symbols allocated to the UCI is determined by the coding rate of the data transmitted along with the UCI and a ratio between the data and the UCI in energy per information bit.
A relatively limited number of symbols are used to transmit UCI in the LTE system (i.e. Rel-8) because only one CC is used for an uplink. That is, there is no big difference in the coding rate of data between UCI transmission and UCI non-transmission, the coding rate of the data needed to calculate the number of symbols allocated to the UCI can be calculated on the assumption that the data occupies all resources allocated to a Physical Uplink Shares CHannel (PUSCH) in the LTE system.
In contrast, the LTE-A system being an evolution of the LTE system supports CA and thus a User Equipment (UE) and an evolved Node B (eNode B or eNB) may use up to five CCs simultaneously. The increased number of CCs leads to an increase in the size of UCI transmitted from the UE. As a consequence, the coding rate of data may be much different between a UCI transmission case and a UCI non-transmission case.
Particularly when UCI is transmitted on a PUSCH in the legacy LTE system, no regard is given to UCI having a large payload size because only methods for transmitting UCI in one CC have been defined.
With a UCI transmission method defined in the LTE system, UCI having a large payload size of up to 15 bits cannot be transmitted. Existing Reed-Muller (RM) coding is not viable for such a large payload size of UCI. Accordingly, there exists a need for developing a new method for transmitting UCI having a large information size in the LTE-A system.